Duct frame opening

ABSTRACT

A duct opening frame, typically supplied in coil form, of flexible, bendable sheet material and adapted to be formed into a frame for attachment to low density, Fiberglas heating, ventilating and cooling ducts to provide means to receive grilles, registers and access doors on the duct.

22 Filed: [21] Appl. No.: 69,163

United States Patent [191 Martin 1 DUCT FRAME OPENING [76] Inventor:Duane P. Martin, 3825 Edgewood Ave., Minneapolis, Minn. 55343 Sept. 2,1970 Related US. Application Data [63] Continuation of Ser. No. 642,634,May 11, 1967,

abandoned.

[52] U.S. C1. 138/103, 98/114 [51] int. Cl. F161 53/00 [58] Field ofSearch 29/190, 183, 193; 285/424; 98/114, 101; 165/50; 138/103 [4June.l1,l974

-\ 2,221,854 11/1940 Zalkind 284/424 X 2,479,741 8/1949 Grim1and....29/190 X 2,566,558 9/1951 Deroo 98/114 2,916,054 12/1959 Callan 285/424X 3,001,805 9/1961 Jones et 211.. 285/424 X 3,340,787 9/1967 Phillips98/114 3,347,569 10/1967 Lindgren..... 285/424 X 3,354,947 11/1967MCKinnOn 165/50 3,386,434 6/1968 Castell et a1. 98/114 X PrimaryExaminer.lerry W. Myracle Attorney, Agent, or FirmWi11iamson, Bains &Moore [57] ABSTRACT A duct opening frame, typically supplied in coilform, of flexible, bendable sheet material and adapted to be formed intoa frame for attachment to low density, Fiberglas heating, ventilatingand cooling ducts to provide means to receive grilles, registers andaccess doors on the duct.

2 Claims, 8 Drawing Figures MTENTEDJUH 1 x 19m 3.815638 sum 10F 2INVENTOR. 0044/5 P M4 emu DUCT FRAME OPENING This is a continuation ofSer. No. 642,634, filed May 11, 1967, now abandoned.

This invention relates to a duct opening frame for Fiberglas heating,ventilating and air conditioning ducts and, more particularly, relatesto a duct opening frame of flexible, bendable sheet material typicallysupplied in coil form to be formed to order with conventional tools andby hand.

Although low density materials, such as Fiberglas, have been availableand used for the past several years for heating, ventilating and airconditioning ducts, a suitable frame for attachment to the duct openingto provide means to receive registers, grilles and access doors thereonhas not heretofore been available. My co-pending application, entitledMETHOD AND AP- PARATUS FOR SUPPORTING AND RETAINING LOW DENSITY WEBS,Ser. No. 494,561, filed Oct. 1 1, 1965, now Pat. No. 3,712,649,discloses and claims supporting and joining apparatus for Fiberglasducts providing a method and means to fabricate a continuous duct systemfrom Fiberglas material. It has been found, however, that in addition tomeans for joining and retaining Fiberglas into a continuous duct system,a frame adapted to be attached to an opening in the duct to providemeans to receive grilles, registers and access doors thereon has becomenecessary to the proper and efficient use of Fiberglas or other lowdensity material in a duct system.

Heating, ventilating and air conditioning duct systems require openingstherein along the system at predetermined intervals. The openings varygreatly in size, depending upon the size of the duct, the length of therun or the size of the room being serviced. Of course, other engineeringdesign requirements affect the selection of the opening size.Consequently, frames must be available to reinforce the duct opening andto be mounted on the duct opening to receive grilles, registers andaccess doors. In the past, frames have been constructed at a factory orshop and shipped to a job site. A multitude of frames sizes must bemanufactured and must be available at the job site. Prefabricated framesare expensive in that a wide variety of sizes must be made and stored bythe manufacturer or contractor. Further, the prefabricated frame isdifficult and time consuming to attach to an opening in the Fiberglasduct. Therefore, the contractor, the manufacturer or the contractor'ssupplier must maintain a large inventory of duct frames which have beenprefabricated so that the contractor may meet the varying engineeringrequirements for the heating, ventilating and air conditioning ductsystems.

With these comments in mind, it is to the elimination of these and otherdisadvantages to which the present invention is directed, along with theinclusion therein of other novel and desirable features.

An object of my invention is to provide a new and improved duct openingframe for attachment to Fiberglas ducts to provide means to assemblegrilles, registers and access doors to the Fiberglas ducts, which ductopening frame is of simple and inexpensive construction and operation.

Another object of my invention is to provide a new and improved ductopening frame which may be supplied in coil form and formed to fit apredetermined opening at the job site with conventional tools and byhand.

Still another object of my invention is the provision of a duct openingframe which is shipped and stored in coil form thereby taking a minimumof storage or shipping volume yet which is manufactured from flexible,bendable sheet material which is easily fabricated on the job byconventional tools and by hand; and which sheet material includes slotsalong the bending lines to decrease bending resistance thereby allowingthe operator to more conveniently bend the duct opening frame to snuglyfit the Fiberglas duct without undue difficulty in performing the bendsby hand.

A further object of my invention is the provision of a duct openingframe for attachment to Fiberglas ducts to provide means to receivegrilles, registers and access doors directly thereon, which duct openingframe is extremely simple in its assembly and operation and will therebypermit quick and easy fabrication and attachment to Fiberglas ducts by aperson of minimum skill and manual dexterity.

These and other objects and advantages of my invention will more fullyappear from the following description made in connection with theaccompanying drawings wherein like reference characters refer to thesame or similar parts throughout the'several views, and in which: FIG. 1is a diagrammatic view of my duct opening frame as it appears inoperation attached to a Fiberglas duct, with a grille mounted thereonand with portions of the components broken away for clarity;

FIG. 2 is a perspective view of my duct opening frame in coilform, shownprior to assembly;

FIG. 3 is a perspective view showing an initial step in the fabricationof my duct opening frame prior to assembly of the duct opening frame toa Fiberglas duct;

FIG. 4 is a perspective view of my duct opening frame as it would appearjust prior to assembly to a Fiberglas duct;

FIG. 5 is a plan view of the novel press clip;

FIG. 6 is a perspective view of the novel press clip shown partiallybent and prior to assembly to a Fiberglas duct;

FIG. 7 is a perspective view showing the alternate embodiment of myinvention assembled to a Fiberglas duct showing a grille mounted thereonand with portions broken away for clarity; and

FIG. 8 is a perspective view of another embodiment of my invention shownin coil form.

In FIG. 1, a Fiberglas duct 10 is shown with a duct opening frame,indicated in general by numeral 11 mounted thereon. The duct openingframe is shown completely assembled with a grille 12 attached thereto byscrews 13. The longitudinal duct opening is indicated by numeral 14 andthe assembled duct opening frame 11 conforms to the opening in the ductin length and depth.

Referring now to FIG. 2, frame 11 is shown in roll or coil form,indicated by numeral 15. The roll comprises a plurality of duct engagingtabs 16 which are bendable along foldline or bendline l7. Longitudinalslots 18 are provided at predetermined intervals along foldline 17 todecrease the bending resistance of tabs 16 as they are bent or folded.The tabs are connected to web-or collar 19. A grille or diffuserreceiving element 20'is foldably attached to web 19 along foldline orbendline 21. Longitudinal slots 22 are provided along foldline 21 atpredetermined intervals to decrease the bending resistance of receivingelement 20 on web 19. Receiving element 20 includes a plurality ofslotted apertures 23, transverse to foldlines I7 and 21 and spacedlongitudinally along receiving element 20. Each receiving elementactually constitutes an outturned flange.

Tab 16 may be provided with inwardly crimped terminal portions 24crimped along foldline 25. These terminal portions may be omitted ifdesired.

Frame 11 is formed from the coil 15 by first notching receiving elementat predetermined intervals longitudinally along the receiving element asit is dispensed from coil 15. The notch is cut with conventional toolsinwardly to foldline 21, and is indicated in FIG. 3 by numeral 26.Similarly, if necessary, a corresponding notch may be made in tabs 16cut inwardly to foldline 17. (This notch is not shown herein). Notches26 are cut in the receiving element at intervals corresponding to thelength and depth of opening 14 in duct 10. The web is then bent at 90along foldlines 27 to form frame 11. The webmay be welded together, ifdesired. In this configuration, an upper lengthwise receiving element20a and a corresponding lower lengthwise receiving element 20b isprovided- Further, a pair of opposed receiving side elements 20c and 20dare provided. In like manner a plurality of upper lengthwise tabs 16aand corresponding lower lengthwise tabs 16b are provided. A pair ofopposed side tabs 16c and tabs 16d are also provided. It should be notedthat the inwardly crimped portions 24 of the tabsprovides ease ininserting the rectangular frame 11 into duct opening 14.

Prior to insertion of the duct opening frame into the duct opening, therespective receiving elements 20a, 20b, 20c and 20d are folded outwardlyat right angles to web 19. The frame, with tabs 16a, 16b, 16c and 16dprojecting outwardly from the respective webs, may then be inserted intoopening 14, as shown in FIG. 4. The outwardly projecting receivingelements abut duct 10 preventing further entry of the frame 11 intoopening 14. At this point, web portions 19a, 19b, 19c and 19d, confrontthe portions of duct 10 which define opening 14 and are snugly abuttedthereagainst. Duct engaging tabs 16a, 16b, 16c and 16d are folded intoduct engaging relation by hand, sandwiching duct 10 between the tabs andthe receiving elements thereby tightly securing frame 11 to duct 10 atopening 14. (See FIG. I)

The duct opening frame is fabricated from 24 gauge galvanized sheetmetal and is die cut to provide the tabs and receiving element therein.Slots 23 and 32 are oneeighth inch wide to receive a No. 8 sheet metalscrew for mounting'of grilles, registers, diffusers and the likethereto. 1 I

An alternate form of my invention is shown in FIG. 5. A pressclip isindicated, in general by numeral 28 and includes a pair of duct engagingtabs or points 29 at each end thereof. A pair of webs 30 areconnected totabs 29. Receiving element 31 is connected to webs 30 therebetween andincludes slotted apertures 32.

Tabs 29 are bendable along foldlines 33 which include slots 34therealong to decrease the bending resistance of tabs 29 relative towebs 30. Webs 30 are foldable relative to receiving element 31 alongfoldlines 35 which include slots 36 therealong to decrease the bendingresistance. Press clip 28 is formed from 24 gauge galvanized sheetmetal. Typically, the press clip is utilized to form a duct openingframe for ducts requiring mounting of a grille, diffuser, register andthe like at transverse openings thereof.

In some instances, the press clips 28 will be utilized to mount and forma duct opening frame in one of the longitudinal walls of a duct ratherthan at the end of the duct as shown in FIG. 7. For example, it may bedesirable to use the press clips 28 in the formation of a duct formingframe in the manner illustrated in FIG. 1. When the press clips are usedin this fashion, the slots 32 in the press clip through which the screwspass will not be formed in the receiving element 31 but will be receivedin one of the webs 30. Specifically, the slots 32 will be formed in thatweb 30 which is presented outwardly. It is also pointed out that whenthe press clips are used to mount and form a frame such as the ductopening frame illustrated inFlG. 1, one of the web portions willpreferably be longer than the other web portion.

A duct 10 is shown in FIG. 7 having transverse opening l4. Press clips28 are spaced along each side of the opening providing four clipsdenoted by numerals 28a, 28b, 28c and 28d. A grille 12' is shown mountedthereon with four screws 13' securing grille 12 to press clips 28 whichare, in turn, securely mounted on duct 10.

Another alternate form of my invention is shown in FIG. 8 which showscoil 15 having receiving element 20' with a plurality of circularopenings 37. The openings are one-eighth inch in diameter to receive No.8 sheet metal screws. Of course, press clip 28 may include circular.openings rather than slotted openings 32 16 bendif desired. Coil 15'includes web 19' and .tabs ably attached thereto- In operation, the ductopening frame of my invention, when utilized to provide a frame for alongitudinal opening on a Fiberglas duct, is formed from coil 15. Theframe size required is determined anda sufficient amount of material,corresponding to the perimeter of opening 14 in duct 10, is uncoiled andcut from the coil. The amount of material which is cut from the coilincludes an extra half inch for overlapping. Next, con.- ventionaltinsnips are used to cut into the receiving element substantially normalto elongate web member 19, at intervals corresponding to the width anddepth dimensions of duct opening 14 with notch 26 proceeding inwardly tofoldline 21. If necessary, duct engaging tabs 16 may be similarly cuttransverse to elongate web member 19, to foldline 17, if necessary.

The material may now be folded transversely at the web member alongfoldlines 27 to form a rectangular frame. As shown in FIG. 3, the frameis partially formed and is ready to be inserted into opening 14. First,receiving elements 20 are folded outwardly along foldlines 21 which areslotted at 22 to decrease the bending resistance. Frame 11 may now beinserted into opening 14 and is pushed into the opening until receivingelements 20 abut duct 10. The installer may now bend tabs 16 outwardlyalong foldline l7 sandwiching the duct between the receiving element andthe duct engaging tabs.

The duct is now properly prepared to receive a register, diffuser,grille or access door. The unit may be attached directly to frame 11,utilizing slotted openings 23 in the receiving element. The slottedopenings are one-eighth inch wide to receive a standard, No. 8 sheetmetal screw.

In some instances, it is desirable to place a grille, diffuser, accessdoor or register on a transverse, either circular or rectangular,opening in a duct system. This may be done by utilizing press clip 28which is folded along foldlines 33 to provide duct engaging tabs 29 toengage duct and then folded along foldlines 35 such that the edge of theduct 14' receives the receiving element 31 so that a unit may be securedthereon.

From the foregoing it will be seen that l have provided a new and novelduct opening frame for use with Fiberglas duct systems which is not onlysimple and efficient in construction and operation, but which is capableof being formed to fit varying size openings in ducts as may benecessary under design requirements. Further, the duct opening frame ofmy invention is provided with slots along foldlines to decrease thebending resistance such that all folds may be made by hand without theneed for any tools whatsoever. This, therefore, greatly speeds up theassembly of my duct opening frame to Fiberglas ducts and results inconsiderable savings in labor costs to the contractor.

It will, of course, be understood that various changes may be made inthe form, details, arrangement and proportions without departing fromthe scope of my inventron.

What is claimed is:

1. In combination with an elongate generally rectangular fiberglass ducthaving a continuous closed peripheral wall, a rectangular opening in theperipheral wall,

a single piece metallic duct opening frame including a substantiallyrectangular collar having opposed substantially parallel pairs of walls,each wall having an inner edge and an outer edge, said collar beingpositioned within and fitting snugly in engaging relation within therectangular opening in the fiberglass duct, each wall of said collarhaving a dimension from the inner edge thereof to the outer edge thereofcorresponding to the thickness dimension of the peripheral wall of thefiberglass duct,

each wall of said collar having a plurality of unigral with the inneredge thereof and being bent to extend outwardly at substantially rightangular relation from a fold line along said outer edge for engaging theexterior surface of the fiberglass duct to clamp the wall of the ductbetween the tabs and the flanges, each flange having a plurality ofspaced apart elongate apertures therein, a plurality of spaced apartopenings in said collar, each of said last-mentioned openings beinglocated along the fold line of one of said flanges,

an accessory frame positioned against said collar,

a plurality of similar press clips securing said accessory frame to saidcollar, each press clip including a generally flat receiving element, apair of web elements integral with said receiving element and extendingat substantially right angular relation thereto, one of said webelements engaging the accessory frame and the other web element andreceiving element engaging the duct, a pair of duct engaging points eachbeing integral with and extending angularly from one of said webelements for penetrating the fiberglass duct, and openings in the pressclip registering with openings in the flanges of the collar and theaccessory frame.

2. The combination as defined in claim 1 wherein the receiving elementof each press clip is of substantially rectangular configuration andwherein the web elements of each press clip are of substantiallyrectangular shaped configuration.

1. In combination with an elongate generally rectangular fiberglass ducthaving a continuous closed peripheral wall, a rectangular opening in theperipheral wall, a single piece metallic duct opening frame including asubstantially rectangular collar having opposed substantially parallelpairs of walls, each wall having an inner edge and an outer edge, saidcollar being positioned within and fitting snugly in engaging relationwithin the rectangular opening in the fiberglass duct, each wall of saidcollar having a dimension from the inner edge thereof to the outer edgethereof corresponding to the thickness dimension of the peripheral wallof the fiberglass duct, each wall of said collar having a plurality ofuniformly spaced apart ducts engaging tabs integral with the inner edgethereof and each being bent to extend outwardly at substantially rightangular relation from a fold line along the inner edge to engage theinterior surface of the fiberglass duct, a plurality of spaced apartopenings in said collar each being located along the fold line of one ofsaid tabs, each wall of said collar having an elongate substantiallyflat generally rectangular shaped flange integral with the inner edgethereof and being bent to extend outwardly at substantially rightangular relation from a fold line along said outer edge for engaging theexterior surface of the fiberglass duct to clamp the wall of the ductbetween the tabs and the flanges, each flange having a plurality ofspaced apart elongate apertures therein, a plurality of spaced apartopenings in said collar, each of said last-mentioned openings beinglocated along the fold line of one of said flanges, an accessory framepositioned against said collar, a plurality of similar press clipssecuring said accessory frame to said collar, each press clip includinga generally flat receiving element, a pair of web elements integral withsaid receiving element and extending at substantially right angularrelation thereto, one of said web elements engaging the accessory frameand the other web element and receiving element engaging the duct, apair of duct engaging points each being integral with and extendingangularly from one of said web elements for penetrating the fiberglassduct, and openings in the press clip registering with openings in theflanges of the collar and the accessory frame.
 2. The combination asdefined in claim 1 wherein the receiving element of each press clip isof substantially rectangular configuration and wherein the web elementsof each press clip are of substantially rectangular shapedconfiguration.